Operational significance of nonclassicality in nonequilibrium Gaussian quantum thermometry

We provide a new operational significance of nonclassicality in nonequilibrium temperature estimation of bosonic baths with Gaussian dynamics and probing with Gaussian states. We find a bound on the thermometry performance using classical probe states. Then we show that by using nonclassical probe states, single-mode and two-mode squeezed vacuum states, one can profoundly improve the classical limit. Interestingly, we observe that this improvement can also be achieved by using Gaussian measurements. Hence, we propose a fully Gaussian protocol for enhanced thermometry, which can simply be realized and used in quantum optics platform.Comment: 4+7 pages; all comments are appreciate